This invention relates to new ruthenium and osmium metal carbene complex compounds and their utility in an improved catalytic process for olefin metathesis polymerization.
During the past two decades, research efforts have enabled an in depth understanding of the olefin metathesis reaction as catalyzed by early transition metal complexes. In contrast, the nature of the intermediates and the reaction mechanism for Group VIII transition metal catalysts has remained elusive. In particular, the oxidation states and ligation of the ruthenium and osmium metathesis intermediates are not known. Furthermore, the discrete ruthenium and osmium carbene complexes isolated to date do not exhibit metathesis activity.
Many ruthenium and osmium metal carbenes have been reported in the literature (for example, see Burrell, A. K., Clark, G. R., Rickard, C. E. F., Roper, W. R., Wright, A. H., J. Chem. Soc., Dalton Trans., 1991, Issue 1, pp. 609-614).